Which scientist first time produced electromagnetic waves in laboratory?

$A$ parallel plate capacitor is completely immersed in a liquid of resistivity $\rho = 0.25 \, \Omega m$ and relative permittivity $\epsilon_r = 80$. If the plates of the capacitor are connected to an alternating voltage source of $V = V_0 \sin(\omega t)$ at a frequency of $f = 0.4 \, GHz$,then the ratio of the amplitudes of the displacement current $(I_d)$ and conduction current $(I_c)$ is:

An accelerated electron produces ...

Which of the following options represents the Ampere-Maxwell Law?

$A$ charged particle oscillates about its mean equilibrium position with a frequency of $8 \times 10^9 \text{ Hz}$. What is the frequency of the electromagnetic waves produced by the oscillator?

An insulator plate is passed between the plates of a capacitor. The displacement current